Sound pressure level calculation methodology investigation of corona noise in AC substations

摘要

In order to improve the measurement accuracy of corona noise in AC substations, the characteristics of different noise sources are measured and analyzed. Wavelet analysis method is employed to decompose the original noisy corona signal. A stop-band comb filter is designed to process the reconstructed approximate coefficient of the decomposed corona noise. The influence of transformer and reactor noises on that of the corona in the substation is eliminated. The speech enhancement technique based on spectral subtraction method is used to extract the pure corona noise form the filtered signal in which the cooling-device noise in included. The proposed method is applied to process field corona noise in a UHV substation. The 1/3-Octave spectrum and the A-weighted sound pressure level of the purified corona noise are calculated.